1. Field of the Invention
The invention relates to a cutter for adhesive paper labels.
2. Description of the Related Art
Such adhesive labels are also referred to as linerless paper. Label paper is understood to mean paper on which the adhesive has been directly applied, which makes the label itself the carrier sheet, and therefore, has adhesive on one side. Specific difficulties exist when cutting such labels sheetsxe2x80x94whether as reel sheets or as single sheets.
The term xe2x80x98linerless paperxe2x80x99 generally describes self-adhesive papers that are usually shaped like strips and rolled into rolls without carrier foil, and that are used to produce self-adhesive labels. Usually, the labels are printed by means of a strip printer using a thermal process and then cut from the strip by means of a cutter.
With regard to the self-adhesive labels on carrier foil, it must be mentioned that the labels are cut to size and positioned on a strip-shaped carrier at short intervals. The carrier material has a wax-life surface that allows the individual labels to be easily separated from the carrier material.
The advantages of linerless paper versus labels on carrier foil include the following:
1. Cost reduction due to elimination of carrier foil.
2. Space savings in the printing mechanism. (More labels on supply reel of same size)
3. Labels of any length can be produced.
4. There is no longer a need to roll up and store the empty carrier foil until the next reel change, which in turn saves construction space in the printing mechanism.
5. The user must no longer dispose of the empty carrier foil.
6. Cost reductions in the printing mechanism, the roll-up device for the carrier foil is not needed.
The following applies to the conventional cutting of linerless paper:
After the printing, the label must be cut to the desired length. This is usually done by means of a cutting mechanism that is driven by an electric motor or an electromagnet and that is positioned downstream from the printing mechanism. The following cutting principles exist:
1. Rotating a circular blade and a spring-attached stationary blade.
2. A shear blade attached with a spring to a stationary cutting strip (Guillotine).
3. A roller blade attached with a spring to a stationary cutting strip.
The aforementioned cutting principles have the disadvantage that the adhesive layer is sheared between two metal blades, which contaminates the blades with glue and the subsequent paper strip adheres to the contaminated blades causing a paper jam.
Blades that are contaminated with glue can frequently only be cleaned with chemicals and are usually difficult to access.
Another problem is the guiding of the paper strip between the printing mechanism and the cutter.
In order to avoid paper jams, fixed paper guiding and cutting elements are coated with non-stick coating in order to prevent the side of the paper that is covered with adhesive from adhering. In spite of the high cost and complexity, such devices still have a high failure rate.
There is therefore a need for further developing a cutter for adhesive paper sheets or label sheets in such a way that the cutting process can be repeated many times without malfunction and without the blade becoming contaminated by glue or the cutting process being disrupted by adhering glue residues.
In one embodiment of a cutter for self-adhesive labels, the cutter has a top part and a bottom part and a feeding gap between the top part and the bottom part. The cutter includes further a cutting mechanism having a blade and coupled to one of the top part and the bottom part. Further, the cutter has a transport and guiding device for the labels, wherein the transport and guiding device includes a transport roll located opposite the cutting mechanism. The feeding gap receives an adhesive paper or label sheet and the transport roll pulls the adhesive paper or label sheet through the feeding gap. The adhesive paper or label sheet passes between the cutting mechanism and the transport roll, and the blade cuts the adhesive paper or label sheet against a curved surface of the transport roll.
An essential characteristic of the invention is that a transport roll lined with an elastomer is located at the exit of the cutting mechanism. The tip of a blade penetrates, at least partly, into the lines of the transport roll, and it is moveable along and over this transport roll parallel to the axis of this transport roll and perpendicular to the transport direction.
From the described technical teaching, there is the essential advantage that because of the positioning of an elastomer transport roll at the exit of the device, now there is the advantage that the adhering paper or label band is pulled through the device and the blade is positioned ahead of the pulling device for the paper band performing the cut directly on the elastomer transport roll.
This provides the advantage that the paper sheet is pulled and no longer pushed through the device, which results in a substantially better guiding of the paper sheets.
Another advantage is that the tip of a simple straight blade penetrates into the elastomer liner of the transport roll providing excellent counter support for the paper sheet to be cut.
First, in sequential order from the top down, the paper sheet is cut and only then does the underlying layer of glue come to rest directly on the transport roll. The advantage of this measure is that the section cut off by the blade does not drop downward, since even after being cut off it is still held by the transport roll, because the cut-off piece still adheres to the transport roll with its glue layer.
This guarantees safe operational handling since the cut-off piece does not simply drop off and adhere to something inadvertently but rather can be taken off and processed further in a defined manner.
With this type of cutting technique there is the additional advantage that there is no need for a counter blade since the cutting support is constituted by the elastomer liner on the transport roll. Therefore, no adjustment problems exist, since even if the blade runs over the transport-roll in a tilted position, proper cutting of the paper sheet can still be guaranteed as long as the blade penetrates by several tenths of a millimeter into the elastomer liner.
This device is both a cutter and a presenter. The label paper with its self-adhesive underside is not pushed over stationary paper guiding and cutting elements but is fed over several rather narrow and easily rotating rolls, one of which is made of a non-stick material and is driven by a stepper motor so that it runs in sync with the printer drive. Since the transport roll is pressed against the top part by a spring, the paper strip is now transported by force through the cutter.
Cutting of the label is performed with a pointed sharp blade perpendicular to the paper strip on the apex line of the transport roll. The initial position of the blade is to the right or to the left at a distance from the paper strip and the transport roll.
In order to cut off the label from the paper strip, the blade that is attached to a guiding element is moved from the right to the left or from the left to the right by way of a spindle that is driven by an electrical motor. In this process the paper strip is cut from the non-adhesive side. The blade can be easily removed from the guide element and reinstalled into it for the purpose of cleaning or replacement.
The cutter consists of essentially two groups of components: the top part, which contains the parts for the cutting of the labels, and the bottom part, which provides the functions xe2x80x9ctransport and guiding of the label material.xe2x80x9d Top and bottom part are connected by a hinge and are locked into a unit by way of a locking bolt.
The support structure of top part and bottom part are pieces cut from profile rods so that cutters can be constructed with varying operational widths without a need for new tool expenses.
All parts are designed so that the hinge can be positioned to the right or to the left by means of only a different assembly and so that the locking flap is always positioned opposite the hinge.
The subject of the present invention not only results from the subjects of the individual claims but also from the combination of these individual claims with each other.